System and method for time division duplexed multiplexing in transmission-reception point to transmission-reception point connectivity

ABSTRACT

A method for operating a transmission-reception point (TRP) includes determining a first cycle of backhaul communications modes for the TRP, each backhaul communications mode of the first cycle is associated with a different time period and prompts the TRP to either transmit or receive using a subset of communications beams available to the TRP during an associated time period, wherein the communications beams used by the TRP and neighboring TRPs of the TRP in each associated time period are selected to prevent mutual interference, and wherein at least one backhaul communications mode of the first cycle prompts the TRP to either transmit or receive using all of the communications beams available to the TRP, determining a backhaul frame configuration for the TRP in accordance with the first cycle, the backhaul frame configuration specifying an arrangement of subframes of a frame used for backhaul communications.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.15/289,638, filed on Oct. 10, 2016, which claims the benefit of U.S.Provisional Application Ser. No. 62/341,877, filed on May 26, 2016,entitled “System and Method for Time Division Duplexed Multiplexing inTransmission Point to Transmission-Reception Point Connectivity,” bothof which applications are hereby incorporated by reference herein intheir entireties.

TECHNICAL FIELD

The present invention relates generally to a system and method fordigital communications, and, in particular embodiments, to a system andmethod for time division duplexed (TDD) multiplexing intransmission-reception point (TRP) to TRP connectivity.

BACKGROUND

Future wireless communications systems are operating at ever highercarrier frequencies in a quest to find greater bandwidth and lessinterference. These wireless communications systems may operate atfrequencies of 6 GHz and above. In order to fully utilize the greaterbandwidth available in the wireless communications systems,transmission-reception points (TRPs) may require more bandwidth and lesslatency than what is afforded in existing backhaul and/or fronthaulconnections. Furthermore the density of the TRPs is likely to be muchhigher than current deployments and the cost of laying wireline highcapacity backhaul connections to all of these TRPs can be prohibitive.Additionally, in certain situations some TRPs may be temporal in natureor mobile and may not be able to support a wireline connection.

SUMMARY

Example embodiments provide a system and method for TDD multiplexing inTRP to TRP connectivity.

In accordance with an embodiment, a method for operating a networkentity in a communications system is provided. The method includestransmitting, by the network entity, a first signal to a plurality oftransmission-reception points (TRPs) indicating a plurality of backhaulcommunication modes. Each backhaul communication mode indicates, to arespective TRP, a corresponding set of beams for backhaul signalcommunication with a different set of TRPs. The corresponding set ofbeams are selected from a plurality of beams including a full set ofcommunication beams of the respective TRP. The method further includestransmitting, by the network entity, a second signal to the plurality ofTRPs indicating a plurality of backhaul frame configurations. Eachbackhaul frame configuration indicates, to the respective TRP, anarrangement of subframes in a frame used for backhaul signalcommunication. In one example, the corresponding set of beams includesthe plurality of beams, a first subset of the plurality of beams lessthan the full set of communication beams of the respective TRP, and asecond subset of the plurality of beams mutually exclusive from thefirst subset. Optionally, in such an example, or in another example, thedifferent set of TRPs includes a plurality of TRPs, a first subset ofthe plurality of TRPs, and a second subset of the plurality of TRPsmutually exclusive from the first subset. Optionally, in any one of theabove mentioned examples, or in another example, each backhaulcommunication mode further indicates a synchronized order oftransmitting and receiving a backhaul signal by each TRP. Optionally, inany one of the above mentioned examples, or in another example, themethod further includes assigning, by the network entity, a TRP-type tothe respective TRP using a scheduling algorithm. The schedulingalgorithm assigns the TRP-type in accordance with a topology of thecommunications system or a capability of the respective TRP. Optionally,in any one of the above mentioned examples, or in another example, themethod further includes assigning, by the network entity, each backhaulcommunication mode to the respective TRP in accordance with a capabilityof the respective TRP or the TRP-type of the respective TRP. Optionally,in any one of the above mentioned examples, or in another example, afirst subset of subframes in the arrangement of subframes is used for acommunication between the respective TRP with one or more userequipments (UEs), and a second subset of subframes in the arrangement ofsubframes corresponds to a special subframe used for backhaulcommunication. Optionally, in any one of the above mentioned examples,or in another example, the method further includes receiving, by thenetwork entity, neighbor lists and TRP capability reports from theplurality of TRPs. Optionally, in any one of the above mentionedexamples, or in another example, the method further includes receiving,by the network entity, neighbor lists and TRP capability reports from anewly deployed TRP or from a TRP in response to a change inconfiguration, a change in capabilities, or a change in neighboringTRPs. Optionally, in any one of the above mentioned examples, or inanother example, the method further includes receiving informationregarding neighbor lists and TRP capability reports during networkplanning. Optionally, in any one of the above-mentioned examples, or inanother example, the network entity is a time division duplexed (TDD)frame configuration entity or a network controlling entity. Optionally,in any one of the above mentioned examples, or in another example,transmitting the second signal further comprises dynamically assigning,by the network entity, a respective time division duplexed (TDD)backhaul frame structure to each TRP. Optionally, in any one of theabove mentioned examples, or in another example, transmitting the secondsignal further comprises semi-statically assigning, by the networkentity, a respective time division duplexed (TDD) backhaul framestructure to each TRP. Optionally, in any one of the above mentionedexamples, or in another example, transmitting the second signal is overa dedicated connection between each of the plurality of TRPs and thenetwork entity.

In accordance with another embodiment, a network entity operating in acommunications system is provided. The network entity includes anon-transitory memory storage including instructions and a processor incommunication with the non-transitory memory storage. The processorexecutes the instructions to transmit a plurality of backhaulcommunication modes to a plurality of transmission-reception points(TRPs). Each backhaul communication mode indicates, to a respective TRP,a corresponding set of beams for backhaul signal communication with adifferent set of TRPs, the corresponding set of beams selected from aplurality of beams including a full set of communication beams of therespective TRP. The processor executes instructions to transmit aplurality of backhaul frame configurations to the plurality of TRPs.Each backhaul frame configuration indicates, to the respective TRP, anarrangement of subframes in a frame used for backhaul signalcommunication. In one example, the corresponding set of beams includesthe plurality of beams, a first subset of the plurality of beams lessthan the full set of communication beams of the respective TRP, and asecond subset of the plurality of beams mutually exclusive from thefirst subset. Optionally, in such an example, or in another example, thedifferent set of TRPs includes a plurality of TRPs, a first subset ofthe plurality of TRPs, and a second subset of the plurality of TRPsmutually exclusive from the first subset. Optionally, in any one of theabove-mentioned examples, or in another example, each backhaulcommunication mode further indicates a synchronized order oftransmitting and receiving a backhaul signal by each TRP. Optionally, inany one of the above-mentioned examples, or in another example,processor executes instructions to assign a TRP-type to the respectiveTRP using a scheduling algorithm. The scheduling algorithm assigns theTRP-type in accordance with a topology of the communications system or acapability of the respective TRP. Optionally, in any one of the abovementioned examples, or in another example, processor executesinstructions to assign each backhaul communication mode to therespective TRP in accordance with a capability of the respective TRP orthe TRP-type of the respective TRP. Optionally, in any one of the abovementioned examples, or in another example, a first subset of subframesin the arrangement of subframes is used for a communication between therespective TRP with one or more user equipments (UEs), and a secondsubset of subframes in the arrangement of subframes corresponds to aspecial subframe used for backhaul communication. Optionally, in any oneof the above mentioned examples, or in another example, the processorexecutes instructions to receive neighbor lists and TRP capabilityreports from the plurality of TRPs. Optionally, in any one of the abovementioned examples, or in another example, the processor executesinstructions to receive neighbor lists and TRP capability reports from anewly deployed TRP or from a TRP in response to a change inconfiguration, a change in capabilities, or a change in neighboringTRPs. Optionally, in any one of the above mentioned examples, or inanother example, processor executes instructions to receive informationregarding neighbor lists and TRP capability reports during networkplanning. Optionally, in any one of the above-mentioned examples, or inanother example, the network entity is a time division duplexed (TDD)frame configuration entity or a network controlling entity. Optionally,in any one of the above mentioned examples, or in another example,transmitting the second signal further comprises semi-staticallyassigning, by the network entity, a respective time division duplexed(TDD) backhaul frame structure to each TRP. Optionally, in any one ofthe above mentioned examples, or in another example, transmitting thesecond signal is over a dedicated connection between each of theplurality of TRPs and the network entity.

In accordance with yet another embodiment, a method for operating anetwork entity in a communications system is provided. The methodincludes assigning, by the network entity, a sequential plurality ofbackhaul communication modes to each of a plurality oftransmission-reception points (TRPs) in the communications system. Eachbackhaul communication mode indicates, to a respective TRP, acorresponding set of beams for a synchronized backhaul signalcommunication with a different set of TRPs. The method further includestransmitting, by the network entity, a signal to each of the pluralityof TRPs indicating the sequential plurality of backhaul communicationmodes to each of the plurality of TRPs. In one example, a first set ofbeams for the synchronized backhaul signal communication and a secondset of beams for the synchronized backhaul signal communication aremutually exclusive. Optionally, in such an example, or in anotherexample, the assigning of the sequential plurality of backhaulcommunication modes is based on a position of each respective TRPrelative to neighboring TRPs. Optionally, in any one of the abovementioned examples, or in another example, each backhaul communicationmode further indicates a synchronized order of transmitting andreceiving a backhaul signal by each TRP. Optionally, in any one of theabove mentioned examples, or in another example, the method furtherincludes assigning, by the network entity, a TRP-type to the respectiveTRP using a scheduling algorithm, the scheduling algorithm assigning theTRP-type in accordance with a topology of the communications system or acapability of the respective TRP. Optionally, in any one of the abovementioned examples, or in another example, the method further includesassigning, by the network entity, each backhaul communication mode tothe respective TRP in accordance with a capability of the respective TRPor the TRP-type of the respective TRP. Optionally, in any one of theabove mentioned examples, or in another example, the method furtherincludes receiving, by the network entity, neighbor lists and TRPcapability reports from the plurality of TRPs, from a newly deployedTRP, or from a TRP in response to a change in configuration, a change incapabilities, or a change in neighboring TRPs. Optionally, in any one ofthe above mentioned examples, or in another example, the network entityis a time division duplexed (TDD) frame configuration entity or anetwork controlling entity.

In accordance with an example embodiment, a method for operating atransmission-reception point (TRP) is provided. The method includesdetermining, by the TRP, a first cycle of backhaul communications modesfor the TRP, each backhaul communications mode of the first cycle isassociated with a different time period and prompts the TRP to eithertransmit or receive using a subset of communications beams available tothe TRP during an associated time period, wherein the communicationsbeams used by the TRP and neighboring TRPs of the TRP in each associatedtime period are selected to prevent mutual interference, and wherein atleast one backhaul communications mode of the first cycle prompts theTRP to either transmit or receive using all of the communications beamsavailable to the TRP, determining, by the TRP, a backhaul frameconfiguration for the TRP in accordance with the first cycle, thebackhaul frame configuration specifying an arrangement of subframes of aframe used for backhaul communications, and communicating, by the TRP,with neighboring TRPs of the TRP in accordance with the first cycle andthe backhaul frame configuration.

In accordance with an example embodiment, a method for operating anetwork entity is provided. The method includes assigning, by thenetwork entity, cycles of backhaul communications modes to TRPs inaccordance with an assigned TRP type of each of the TRPs, and assigning,by the network entity, backhaul frame configurations to the TRPs inaccordance with the assigned TRP type of each of the TRPs.

In accordance with an example embodiment, a TRP is provided. The TRPincludes a processor, and a computer readable storage medium storingprogramming for execution by the processor. The programming includinginstructions to configure the TRP to determine a first cycle of backhaulcommunications modes for the TRP, each backhaul communications mode ofthe first cycle is associated with a different time period and promptsthe TRP to either transmit or receive using a subset of communicationsbeams available to the TRP during an associated time period, wherein thecommunications beams used by the TRP and neighboring TRPs of the TRP ineach associated time period are selected to prevent mutual interference,and wherein at least one backhaul communications mode of the first cycleprompts the TRP to either transmit or receive using all of thecommunications beams available to the TRP, determine a backhaul frameconfiguration for the TRP in accordance with the first cycle, thebackhaul frame configuration specifying an arrangement of subframes of aframe used for backhaul communications, and communicate with neighboringTRPs of the TRP in accordance with the first cycle and the backhaulframe configuration.

In accordance with an example embodiment, a network entity is provided.The network entity includes a processor, and a computer readable storagemedium storing programming for execution by the processor. Theprogramming including instructions to configure the network entity toassign cycles of backhaul communications modes to TRPs in accordancewith an assigned TRP type of each of the TRPs, and assign backhaul frameconfigurations to the TRPs in accordance with the assigned TRP type ofeach of the TRPs.

Practice of the foregoing embodiments enables each TRP to exchange dataand/or control information with each of its direct neighbors, enablingfull multi-point connectivity between TRPs with minimal overhead.

Practice of the foregoing embodiments avoids cross-interference, e.g.,uplink vs downlink, between adjacent sectors.

Practice of the foregoing embodiments integrates into a 5G mmWave TDDframe structure for access and can adaptively change the uplink and/ordownlink subframes for the backhaul (or fronthaul) to suit the demandsof the respective TRPs. This may be done in a semi-static or dynamicway.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present disclosure, and theadvantages thereof, reference is now made to the following descriptionstaken in conjunction with the accompanying drawings, in which:

FIG. 1 illustrates an example wireless communications system accordingto embodiments presented herein;

FIG. 2A illustrates example subframe structures for frames N and N+1according to embodiments presented herein;

FIG. 2B illustrates an example communications system highlightingcommunications between sectors and Cells (i.e., eNBs) during the Ssubframes shown in FIG. 2A according to embodiments presented herein;

FIG. 2C illustrates an example TDD frame format for signaling frameconfiguration information between eNBs using a dedicated connectionaccording to embodiments presented herein;

FIG. 3A illustrates a bandwidth allocation diagram of a frequency bandused for a high frequency backhaul link where access uses a differentfrequency band according to embodiments presented herein;

FIG. 3B illustrates bandwidth allocation diagrams of a frequency bandused for a high frequency backhaul link where access uses the samefrequency band according to embodiments presented herein;

FIGS. 4A and 4B illustrate prior art techniques for multiplexingbeam-formed mmWave fronthaul transmissions/receptions from a legacy basestation (4G base stations) to and from a set of 5G small cells that areplaced between the 4G base stations according to embodiments presentedherein;

FIG. 5A illustrates a TRP and coverage area highlighting a firstbackhaul mode for the TRP where the TRP transmits using its fullcomplement of communications beams according to embodiments presentedherein;

FIG. 5B illustrates a TRP and coverage area highlighting a secondbackhaul mode for the TRP where the TRP receives using a first set ofcommunications beams according to embodiments presented herein;

FIG. 5C illustrates a TRP and coverage area highlighting a thirdbackhaul mode for the TRP where the TRP receives using a second set ofcommunications beams according to embodiments presented herein;

FIGS. 6A-6C illustrate diagrams of a portion of a communications systemhighlighting TRPs operating in different first example backhaul modes tofacilitate a high frequency backhaul link according to embodimentspresented herein;

FIG. 7A illustrates a TRP and coverage area highlighting a firstbackhaul mode for the TRP where the TRP receives using its fullcomplement of communications beams according to embodiments presentedherein;

FIG. 7B illustrates a TRP and coverage area highlighting a secondbackhaul mode for the TRP where the TRP transmits using a first set ofcommunications beams according to embodiments presented herein;

FIG. 7C illustrates a TRP and coverage area highlighting a thirdbackhaul mode for the TRP where the TRP transmits using a second set ofcommunications beams according to embodiments presented herein;

FIGS. 8A-8C illustrate diagrams of a portion of a communications systemhighlighting TRPs operating in different second example backhaul modesto facilitate a high frequency backhaul link according to embodimentspresented herein;

FIGS. 9A-9C illustrate diagrams of backhaul modes of a first set ofbackhaul modes for a first TRP type according to embodiments presentedherein;

FIGS. 9D-9G illustrate diagrams backhaul modes of a second set ofbackhaul modes for second and third TRP types according to embodimentspresented herein;

FIGS. 10A-10D illustrate diagrams of a portion of a communicationssystem highlighting TRPs operating in different example sets of backhaulmodes to facilitate a high frequency backhaul link according toembodiments presented herein;

FIG. 11 illustrates an example frame structure with an extended subframeused to carry the TDD subframes for high frequency backhaul link supportaccording to embodiments presented herein;

FIG. 12 illustrates TDD frame configurations for 3GPP LTE-A according toembodiments presented herein;

FIG. 13 illustrates an example TDD frame format for supporting the highfrequency backhaul link according to embodiments presented herein;

FIG. 14 illustrates a generalized communications system according toembodiments presented herein;

FIG. 15 illustrates example ways for a TRP to obtain TDD backhaul frameconfigurations according to embodiments presented herein;

FIGS. 16A and 16B illustrate example deployments for urban areasaccording to embodiments presented herein;

FIG. 17 illustrates a flow diagram of example operations occurring in anetwork entity performing backhaul mode to TDD backhaul subframe mappingaccording to embodiments presented herein;

FIG. 18 illustrates a flow diagram of example operations occurring in aTRP communicating using a high frequency backhaul link according toembodiments presented herein;

FIG. 19 illustrates a block diagram of an embodiment processing systemfor performing methods described herein; and

FIG. 20 illustrates a block diagram of a transceiver adapted to transmitand receive signaling over a telecommunications network according toembodiments presented herein.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

The making and using of the presently example embodiments are discussedin detail below. It should be appreciated, however, that the presentdisclosure provides many applicable inventive concepts that can beembodied in a wide variety of specific contexts. The specificembodiments discussed are merely illustrative of specific ways to makeand use the embodiments, and do not limit the scope of the disclosure.

FIG. 1 illustrates an example wireless communications system loftCommunications system 100 includes an evolved NodeB (eNB) 105 serving aplurality of user equipments (UEs), such as UE 110, UE 112, and UE 114.In a first operating mode, transmissions for UEs as well astransmissions by UEs pass through the eNB. The eNB allocates networkresources for the transmissions to or from the UEs. eNBs may also becommonly referred to as base stations, NodeBs, master eNBs (MeNBs),secondary eNBs (SeNBs), remote radio heads, access points, and the like,while UEs may also be commonly referred to as mobiles, mobile stations,terminals, subscribers, users, stations, and the like. A base station(or an eNB, NodeB, remote radio head, access point, transmission point,transmit-receive point and so on) that is serving one or more UEs may bereferred to as a serving base station (SBS). A transmission point may beused to refer to any device capable of transmitting. Therefore,transmission-reception points (TRP) commonly refer to eNBs, basestations, NodeBs, remote radio heads, access points but can also includeUEs, mobiles, mobile stations, terminals, subscribers, users, and thelike.

While it is understood that communications systems may employ multipleeNBs (or TRPs) capable of communicating with a number of UEs, only oneeNB, and a number of UEs are illustrated for simplicity.

A cell is a commonly used term that refers to a coverage area of an eNB.Typically, a cell is served by one or more sectors of a sectorizedantenna of the eNB. Hence, the coverage area of the eNB includes a cellpartitioned into a plurality of sectors. As an illustrative example, ina scenario where an eNB uses a three-sector antenna system, the cell ofthe eNB may be divided into three sectors, with each sector beingcovered by a separate antenna (with an example beam width of 120degrees) or a separate part of the total antenna system. As anotherillustrative example, in a scenario where an eNB uses a six-sectorantenna system (where each antenna may cover a 60 degree sector, forexample), the cell of the eNB may be divided into six sectors or threesectors, with each sector being covered by one or two antennas or partssectors of the antenna system respectively.

In co-assigned U.S. Patent application publication number US2016/0183232A1, filed Nov. 13, 2015, entitled “System and Method forInterference Coordination in Cellular Millimeter Wave CommunicationsSystems,” which is hereby incorporated herein by reference, an examplesimple time division duplexed (TDD) scheme for fast TRP to TRPcommunications using a millimeter wave (mmWave) backhaul is presented. Agoal of the techniques presented therein was to show that neighboringTRPs may exchange control information on a frame by frame basis (muchfaster than the present X2 interface) to support features of the exampleembodiments presented therein, which was for transmission beam blankingto support TDD in mmWave communications systems

FIG. 2A illustrates example subframe structures 200 for frames N 205 andN+1 210. In an S subframe 215 of frame N 205, a TRP serving sector C ofCell 1 communicates with a TRP serving sector A of Cell 2 and a TRPserving sector A of Cell 3 (shown as downward pointing arrows), while inan S subframe 220 of frame N+1 210, a TRP serving sector A of Cell 2 anda TRP serving sector A of Cell 3 communicate with a TRP of sector C ofCell 1 (shown as upward pointing arrows). FIG. 2B illustrates an examplecommunications system 230 highlighting communications between TRPsserving the different sectors and cell coverage areas during the Ssubframes shown in FIG. 2A. It is noted that the beams used in TRP toTRP communications are at least partially blanked, and are referred toas blanked beams.

FIG. 2C illustrates an example TDD frame format 260 for signaling frameconfiguration information between TRPs using a dedicated connection (asopposed to using the more conventional X2 link). As shown in FIG. 2C, aguard period (GP) 265 in an S subframe 267 may be used in conjunctionwith the blanked beams to communicate the frame configurationinformation between TRPs, which may advantageously reuse the beamforminghardware since no data is transmitted at this time. The frameconfiguration information may include the chosen TDD frame configurationand one or more of the following:

-   -   a set of beam indices used;    -   an almost blank flag(s) bit; and    -   a reschedule flag(s).

The frame configuration information may be transmitted in a firstportion 270 of an overall mmWave band 275, which is allocated forbackhaul/fronthaul use, while a second portion 280 is allocated foraccess, e.g., mmWave access where mmWave devices are able to receive ortransmit using cellular-based techniques. The situation where a separateportion of the available bandwidth is dedicated for exchange of frameconfiguration information will be referred to as out of band signaling.In addition to or as an alternative to the reuse of bandwidth availablein the blanked subframes, the backhaul X2 interface may be used tosignal this control information.

FIG. 2C also illustrates out of band signaling (although still withinoverall band(s) 275) with any frame format (TDD and/or FDD (as shown inFIG. 2C)). Existing beamforming hardware may be reused in the GP of Ssubframes, such as S subframe 267, of TDD frames. Inband signaling(where a part of the bandwidth dedicated for other communications isused, e.g., using the second portion 280 to exchange frame configurationinformation) may also be used in the S subframes of TDD frames.

It is noted however, that a TRP to TRP link may operate in a more globalcellular basis and not just be considered as a single link. Furthermore,future UE centric (cloud cell and virtual cell concepts) for ultra-densenetworks (UDNs), a fast, high capacity, low latency TRP to TRP link maybe required (e.g., a fronthaul and/or a backhaul), since user data mayneed to be transported (e.g., exchanged) from one TRP to another for avariety of reasons, including:

-   -   It is likely that not every TRP in a UE centric cell will have a        dedicated connection to a switching gateway (via an S1 bearer).        The switching gateway is a higher level network entity        responsible for providing connectivity between TRPs. Many UE        centric concepts propose that only a master TRP (or a head-node        of a UE centric cell) will be connected to the switching gateway        (via a wired or wireless connection) and the master TRP will        distribute the user data to the other TRPs in the UE centric        cell to support different communications modes.    -   As the UE moves through a group of TRPs, the set of TRPs for        each UE centric cell will change in a very dynamic way and user        data may need to be exchanged between TRPs to ensure that the        user data is present for transmissions to the UE.

FIGS. 2A-2C are illustrations of techniques presented in co-assignedU.S. patent application Ser. No. 14/941,243.

According to an example embodiment, a high bandwidth, low latency linkreplaces or complements the current X2 link. The link may be referred toas either a backhaul or a fronthaul depending on the architecture of thecommunications system. The term backhaul will be used interchangeablywith the term fronthaul although in some definitions they may bedifferent. The link may utilize the spectrum at 6 GHz and above (e.g.,the 15 GHz, 28 GHz, 38/39 GHz, 70-80 GHz, and so forth, spectrum bands)and the link shall be referred to as an mmWave backhaul of an mmWavecommunications system. A communications system operating at highfrequencies will need to use beamforming to compensate for the highpathloss present at the high carrier frequencies. The backhaul link maybe used for a cellular communications system where access(cellular-based connectivity) is operating below 6 GHz (e.g., 3GPP LTE-Acompliant communications systems) or when access is also using the highcarrier frequencies (at least in part).

FIG. 3A illustrates a bandwidth allocation diagram 300 of a frequencyband used for a high frequency backhaul link where access uses adifferent frequency band. As shown in FIG. 3A, the entirety of thefrequency band used for the high frequency backhaul link is usable bythe high frequency backhaul link since access uses a different frequencyband. FIG. 3B illustrates bandwidth allocation diagrams of a frequencyband used for a high frequency backhaul link where access uses the samefrequency band as the backhaul link. A first bandwidth allocationdiagram 350 illustrates a situation wherein the high frequency band isshared between the backhaul link and access using frequency divisionmultiple access (FDMA) and is partitioned into at least two portions,with a first high frequency portion is allocated to the backhaul linkand a second high frequency portion allocated to the access. A secondbandwidth allocation diagram 370 illustrates a situation wherein thefrequency band is shared between the high frequency backhaul link andaccess using time division multiple access (TDMA) or spatial divisionmultiple access (SDMA). If TDMA is used, the backhaul link is assignedto use the high frequency band at specific times and the access isassigned to use the high frequency band at other specific times. If SDMAis used, the high frequency backhaul link is assigned to use thefrequency band only in specific spatial orientations (or beamdirections) and the access is assigned to use the same frequency band inother specific spatial orientations (or beam directions), where thespatial orientations may change as a function of time.

According to an example embodiment, the high frequency backhaul link hasthe flexibility to change its data rate in different directionsdepending on the requirement of each TRP. Since each TRP may be servingUEs with different uplink and downlink ratios for access (by way ofdifferent chosen TDD frame structures for access, for example), the highfrequency backhaul link may also need to change its own data rate tosupport the TRPs. As an illustrative example, if the uplink to downlinkratio is very small (i.e., uplink much smaller than downlink), the highfrequency backhaul link changes its downlink data rate to allow for thetransfer of more downlink data to the TRPs to meet TRP requirements.

According to an example embodiment, TDMA is used to multiplex the usageof the high frequency band between the high frequency backhaul link andaccess. Although the usage of the high frequency band could bemultiplexed for the high frequency backhaul link and access by usingFDMA, TDMA may be particularly attractive since the capacity between thehigh frequency backhaul link and access can be dynamically changed tomeet demand, and this is generally easier with TDMA than with FDMA. WithSDMA, sufficient isolation between access and the high frequencybackhaul link may be difficult to guarantee for all deployments.

FIGS. 4A and 4B illustrate prior art techniques for multiplexingbeamformed mmWave fronthaul transmissions/receptions from a legacy basestation (4G base stations) to and from a set of 5G small cells that areplaced between the 4G base stations. FIG. 4A is presented in R. Taoriand A. Sridhanen, “Point-to-Multipoint In-Band mmWave Backhaul for 5GNetworks”, IEEE Communications Magazine, January 2015 and FIG. 4B ispresented in US Patent publication number 2015/0036571 A1—“Transmissionand scheduling for wireless front haul”, both of which are herebyincorporated herein by reference. The 4G base stations have wiredbackhaul connections (labeled W-BS) and the 5G base stations (labeledU-BS) are placed between the wired 4G base stations. Techniques enablingeach wired 4G base station to each 5G base station are presented. Theprior art techniques disclose that each unwired 5G base station isconnected to each wired 4G base station under certain deployment mixesof 4G and 5G base stations. As such, there is no accommodation forneighboring 5G TRPs (base stations) to have direct connections with eachother. If neighboring 5G TRPs want to exchange information (controland/or data), the information would have to be relayed through the W-BS,which would lead to latency and capacity issues. As an example, becauseeach TRP to TRP exchange has to be processed by the W-BS, latencycorresponding to multiple frames and/or subframes as well as W-BSprocessing is incurred. As another example, each TRP to TRP exchangeuses (and therefore are limited to) the capacity of the W-BS to U-BSlink. Finally, the prior art techniques are not applicable to allpossible deployments.

According to an example embodiment, a multiplexing scheme that supportsa high frequency backhaul link from each TRP to all of its neighboringTRPs is provided, where the neighboring TRPs may or may not haveconnectivity to the switching gateway. At first glance, the problemlooks relatively simple. A solution, such as proposed in the co-assignedU.S. patent application Ser. No. 14/941,243, where TDD transmissionsacross each cell edge may be used. However, the solution does notaddress a situation where all TRPs have to communicate with each otherinstead of just one TRP communicating with other TRPs. Furthermore, aproposed solution should not require adjacent antenna arrays of a singleTRP to be in transmit and receive modes at the same time to reduce crossinterference.

According to an example embodiment, TDD techniques enabling highfrequency backhaul links connecting a TRP to each of its neighbors arepresented. The TDD techniques utilize as few subframes as possible toreduce latency.

According to an example embodiment, each TRP has an integer number ofbackhaul modes of operation for communicating on the high frequencybackhaul link. Within each backhaul mode of operation, a TRP performsdownlink transmissions or uplink receptions and not both downlink anduplink. Between backhaul modes of operation, a TRP can switchcommunications mode, e.g., from downlink to uplink or uplink todownlink, or remain in the same communications mode, e.g., downlink todownlink or uplink to uplink. Every TRP uses the same backhaul modes ofoperation, but different TRP types perform different backhaul modes in agiven time period. The assignment of the backhaul modes is made based onTRP type, where TRP type may be assigned manually or algorithmically,for example. The TRPs sequentially cycle through the backhaul modes.

According to an example embodiment, each TRP has three (3) backhaulmodes of operations for communicating on the high frequency backhaullink. In a first backhaul mode, the TRP communicates (sends or receives)with all of its neighboring TRPs using its full complement ofcommunications beams. In a second backhaul mode, the TRP communicates(receives or sends) with a first set of its neighboring TRPs using afirst set of its communications beams, and in a third backhaul mode, theTRP communicates (receives or sends) with a second set of itsneighboring TRPs using a second set of its communications beams. Acombination of the first set of neighboring TRPs and the second set ofneighboring TRPs make up all of the neighboring TRPs. Additionally, thefirst set of neighboring TRPs and the second set of neighboring TRPs maybe mutually exclusive. A combination of the first set of communicationsbeams and the second set of communications beams make up the fullcomplement of communications beams. Furthermore, the first set ofcommunications beams and the second set of communications beams aremutually exclusive.

The TRP and its neighboring TRPs may switch backhaul modes on a subframebasis. Switching backhaul modes each subframe helps to reduce thelatency associated with the high frequency backhaul link. Alternatively,the TRP and its neighboring TRPs may switch backhaul modes following aspecified pattern of subframes. As an illustrative example, The TRP andits neighboring TRPs switches backhaul modes every N-th subframe, whereN is equal to 1, 2, 3, 4, and so on. As another illustrative example,the TRP and its neighboring TRPs may remain in different backhaul modesfor different numbers of subframes. The TRPs start at different backhaulmodes, dependent upon each TRP's relationship to a starting TRP. A firstTRP may start with the first backhaul mode as its initial mode, whilesome TRPs that are immediate neighbors of the first TRP (i.e., somefirst order neighbors) may start with the second backhaul mode as theirinitial mode, and other TRPs that are also first order neighbors (i.e.,other closest neighbors) may start with the third backhaul mode as theirinitial mode, and so on. A scheduling algorithm may be used to determineinitial backhaul modes for the TRPs of a communications system.Alternatively, the initial backhaul modes may be specified manually.

According to an example embodiment, a first backhaul mode comprises theTRP transmitting to all of its neighboring TRPs using its fullcomplement of communications beams, a second backhaul mode comprises theTRP receiving from a first set of its neighboring TRPs using a first setof communications beams, and a third backhaul mode comprises the TRPreceiving from a second set of its neighboring TRPs using a second setof communications beams. A combination of the first set ofcommunications beams and the second set of communications beams make upthe full complement of communications beams. Furthermore, the first setof communications beams and the second set of communications beams aremutually exclusive.

FIG. 5A illustrates a TRP and coverage area 500 highlighting a firstbackhaul mode for the TRP where the TRP transmits using its fullcomplement of communications beams. Transmitting using the fullcomplement of communications beams, enables the TRP to transmit to allof its closest neighboring TRPs.

FIG. 5B illustrates a TRP and coverage area 530 highlighting a secondbackhaul mode for the TRP where the TRP receives using a first set ofcommunications beams. Receiving using the first set of communicationsbeams, enables the TRP to receive from a first subset of its closestneighboring TRPs. As shown in FIG. 5B, the first set of communicationsbeams comprises half of the TRP's full complement of communicationsbeams, therefore, the TRP is able to receive from approximately half ofits closest neighboring TRPs.

FIG. 5C illustrates a TRP and coverage area 560 highlighting a thirdbackhaul mode for the TRP where the TRP receives using a second set ofcommunications beams. Receiving using the second set of communicationsbeams, enables the TRP to receive from a second subset of its closestneighboring TRPs. The first set of communications beams shown in FIG. 5Band the second set of communications beams are mutually exclusive. Asshown in FIG. 5C, the second set of communications beams comprises halfof the TRP's full complement of communications beams, therefore, the TRPis able to receive from approximately half of its closest neighboringTRPs. Because the first set and the second set are mutually exclusive,between the second backhaul mode and the third backhaul mode, the TRP isable to receive from all of the closest neighboring TRPs.

FIGS. 6A-6C illustrate diagrams of a portion of a communications systemhighlighting TRPs operating in different first example backhaul modes tofacilitate a high frequency backhaul link. Within any given time period,the backhaul mode of a TRP is determined based on the position of theTRP relative to its neighboring TRPs. A scheduling algorithm may be usedto determine the mode of the TRPs of the communications system.Alternatively, the modes of the TRPs of the communications system may bedetermined from a memory/database, a network entity, neighboring TRPs,or a combination thereof. Diagram 600 (FIG. 6A) illustrates the backhaulmodes of the TRPs during a first time period. During the first timeperiod, a first TRP 605 (labeled Type C) is set to operate in the secondbackhaul mode (receive using a first set of communications beams). Afirst subset of the neighboring TRPs (labeled Type A) of first TRP 605,e.g., second TRP 607, third TRP 609, and fourth TRP 611, are set tooperate in the first backhaul mode (transmit using their full complementof communications beams) and a second subset of the neighboring TRPs(which are labeled Type B) of first TRP 605, e.g., fifth TRP 613, sixthTRP 615, and seventh TRP 617, are set to operate in the third backhaulmode (receive using a second set of communications beams). The backhaulmodes of the TRPs during the first time period are referred to as theinitial backhaul modes of the TRPs. It is noted that the initialbackhaul modes of the TRPs shown in FIG. 6A are only examples presentedfor illustration and discussion. The initial backhaul modes may differif the communications beams differ, the topology of the communicationssystem differs, different implementation choices are made, differentsets of communications beams, and so forth. Other initial backhaul modesare possible, as long as the relations between TRPs shown in FIG. 6A aremaintained.

Diagram 630 (FIG. 6B) illustrates the backhaul modes of the TRPs duringa second time period. During the second time period, first TRP 605 isset to operate in the third backhaul mode (receive using the second setof communications beams), while the first subset of neighboring TRPs offirst TRP 605 (labeled Type A), e.g., second TRP 607, third TRP 609, andfourth TRP 611, are set to operate in the second backhaul mode (receiveusing the first set of communications beams) and a second subset of theneighboring TRPs of first TRP 605 (labeled Type B), e.g., fifth TRP 613,sixth TRP 615, and seventh TRP 617, are set to operate in the firstbackhaul mode (transmit using their full complement of communicationsbeams). In other words, each TRP sequentially changes to the nextbackhaul mode. As an example, if a TRP was operating in the firstbackhaul mode in the first time period, in the second time period theTRP will operate in the second backhaul mode. Similarly, if a TRP wasoperating in the third backhaul mode in the first time period, in thesecond time period the TRP will operate in the first backhaul mode. Theconsistent cycling through of the different backhaul modes enables theTRPs to communicate without causing undue interference.

Diagram 660 (FIG. 6C) illustrates the backhaul modes of the TRPs duringa third time period. During the third time period, first TRP 605 is setto operate in the first backhaul mode (transmit using their fullcomplement of communications beams), while the first subset ofneighboring TRPs of first TRP 605 (labeled Type A), e.g., second TRP607, third TRP 609, and fourth TRP 611, are set to operate in the thirdbackhaul mode (receive using the second set of communications beams) anda second subset of the neighboring TRPs of first TRP 605 (labeled typeB), e.g., fifth TRP 613, sixth TRP 615, and seventh TRP 617, are set tooperate in the second backhaul mode (receive using the first set ofcommunications beams).

Table 1 illustrates example backhaul modes for different TRP types, withD representing downlink communications, and U representing uplinkcommunications.

TABLE 1 Example backhaul modes. Cell Type Sub-frame 1 Sub-frame 2Sub-frame 3 A D (full) U (mode 2) U (mode 3) B U (mode 3) D (full) U(mode 2) C U (mode 2) U (mode 3) D (full)

The subframes may be in a different time order, i.e., the informationshown in Table 1 is just for discussion purposes. It is important thatthe backhaul modes are synchronized with TRP types as shown in thediscussion. The information shown in Table 1 allows for one completedownlink and uplink transmission set per sector. Multiple downlinksand/or uplinks may be needed and may be dynamically assigned dependingupon the chosen TDD frame structure. Further discussion of this ispresented below. Unlike TDD for access (eNB to UE communications), thepropagation delay between TRPs is known, so S subframes between thedownlink and uplink subframes are not needed. The TRP to TRP delays maybe incorporated into guard times, for example.

According to an example embodiment, a first backhaul mode comprises theTRP receiving from all of its neighboring TRPs using its full complementof communications beams, a second backhaul mode comprises the TRPtransmitting to a first set of its neighboring TRPs using a first set ofcommunications beams, and a third backhaul mode comprises the TRPtransmitting to a second set of its neighboring TRPs using a second setof communications beams. A combination of the first set of neighboringTRPs and the second set of neighboring TRPs make up all of theneighboring TRPs. Additionally, the first set of neighboring TRPs andthe second set of neighboring TRPs may be mutually exclusive. Acombination of the first set of communications beams and the second setof communications beams make up the full complement of communicationsbeams. Furthermore, the first set of communications beams and the secondset of communications beams are mutually exclusive. This approach hassome advantage over the previous approach as a TRP receiving using itsfull complement of communications beam and transmitting using onlysubsets of the full complement of communications beams, requires a lowernumber of power amplifiers (PAs) at the TRP, than if the TRP istransmitting using the full complement of communications beams.

FIG. 7A illustrates a TRP and coverage area 700 highlighting a firstbackhaul mode for the TRP where the TRP receives using its fullcomplement of communications beams. Receiving using the full complementof communications beams, enables the TRP to receive from all of itsclosest neighboring TRPs.

FIG. 7B illustrates a TRP and coverage area 730 highlighting a secondbackhaul mode for the TRP where the TRP transmits using a first set ofcommunications beams. Transmitting using the first set of communicationsbeams, enables the TRP to transmit to a first subset of its closestneighboring TRPs. As shown in FIG. 7B, the first set of communicationsbeams comprises half of the TRP's full complement of communicationsbeams, therefore, the TRP is able to transmit to approximately half ofits closest neighboring TRPs.

FIG. 7C illustrates a TRP and coverage area 760 highlighting a thirdbackhaul mode for the TRP where the TRP transmits using a second set ofcommunications beams. Transmitting using the second set ofcommunications beams, enables the TRP to transmit to a second subset ofits closest neighboring TRPs. The first set of communications beams andthe second set of communications beams are mutually exclusive. As shownin FIG. 7C, the second set of communications beams comprises half of theTRP's full complement of communications beams, therefore, the TRP isable to transmit to half of its closest neighboring TRPs. Because thefirst set and the second set are mutually exclusive, between the secondbackhaul mode and the third backhaul mode, the TRP is able to transmitto all of its closest neighboring TRPs.

FIGS. 8A-8C illustrate diagrams of a portion of a communications systemhighlighting TRPs operating in different second example backhaul modesto facilitate a high frequency backhaul link. Within any given timeperiod, the backhaul mode of a TRP may be determined based on theposition of the TRP relative to its neighboring TRPs. A schedulingalgorithm may be used to determine the mode of the TRPs of thecommunications system. Diagram 800 (FIG. 8A) illustrates the backhaulmodes of the TRPs during a first time period. During the first timeperiod, a first TRP 805 is set to operate in the second backhaul mode(transmit using a first set of communications beams). A first subset ofthe neighboring TRPs of first TRP 805 (labeled type A), e.g., second TRP807, third TRP 809, and fourth TRP 811, are set to operate in the firstbackhaul mode (receive using their full complement of communicationsbeams) and a second subset of the neighboring TRPs of first TRP 805(labeled type B), e.g., fifth TRP 813, sixth TRP 815, and seventh TRP817, are set to operate in the third backhaul mode (transmit using asecond set of communications beams). The backhaul modes of the TRPsduring the first time period are referred to as the initial backhaulmodes of the TRPs. It is noted that the initial backhaul modes of theTRPs shown in FIG. 8A are only examples presented for illustration anddiscussion. The initial backhaul modes may differ if the communicationsbeams differ, the topology of the communications system differs,different implementation choices are made, different sets ofcommunications beams, and so forth. Other initial backhaul modes arepossible, as long as the relations between TRPs shown in FIG. 8A aremaintained.

Diagram 830 (FIG. 8B) illustrates the backhaul modes of the TRPs duringa second time period. During the second time period, first TRP 805 isset to operate in the third backhaul mode (transmit using the second setof communications beams), while the first subset of neighboring TRPs offirst TRP 805 (labeled type A), e.g., second TRP 807, third TRP 809, andfourth TRP 811, are set to operate in the second backhaul mode (transmitusing the first set of communications beams) and a second subset of theneighboring TRPs of first TRP 805 (labeled Type B), e.g., fifth TRP 813,sixth TRP 815, and seventh TRP 817, are set to operate in the firstbackhaul mode (receive using their full complement of communicationsbeams). In other words, each TRP sequentially changes to the nextbackhaul mode. As an example, if a TRP was operating in the firstbackhaul mode in the first time period, in the second time period theTRP will operate in the second backhaul mode. Similarly, if a TRP wasoperating in the third backhaul mode in the first time period, in thesecond time period the TRP will operate in the first backhaul mode. Theconsistent cycling through of the different backhaul modes enables theTRPs to communicate without causing undue interference.

Diagram 860 (FIG. 8C) illustrates the backhaul modes of the TRPs duringa third time period. During the third time period, first TRP 805 is setto operate in the first backhaul mode (receive using their fullcomplement of communications beams), while the first subset ofneighboring TRPs of first TRP 805 (labeled Type A), e.g., second TRP807, third TRP 809, and fourth TRP 811, are set to operate in the thirdbackhaul mode (transit using the second set of communications beams) anda second subset of the neighboring TRPs of first TRP 805 (labeled TypeB), e.g., fifth TRP 813, sixth TRP 815, and seventh TRP 817, are set tooperate in the second backhaul mode (transmit using the first set ofcommunications beams).

Table 2 illustrates example backhaul modes for different TRP types, withD representing downlink communications, and U representing uplinkcommunications.

TABLE 2 Example backhaul modes for different TRP types. Cell TypeSub-frame 1 Sub-frame 2 Sub-frame 3 A U (full) D (mode 2) D (mode 3) B D(mode 3) U (full) D (mode 2) C D (mode 2) D (mode 3) U (full)

According to an example embodiment, some TRP types have differentbackhaul modes that are determined and assigned based on the TRP type aswell as their individual beamforming capabilities, where at least someof the different TRP types cycle through different sets of backhaulmodes. If there are differences in the number of modes per different setof backhaul modes, TRPs using the set of backhaul modes with fewer modesmay remain idle after they have cycled through their respective set ofbackhaul modes to permit the other TRPs using the different sets ofbackhaul modes to complete their cycles. Although there are differentsets of backhaul modes, all TRPs of a TRP type assigned to a set ofbackhaul modes will use the same set of backhaul modes. Furthermore, allTRPs cycle through the backhaul modes at the same rate. The use ofdifferent sets of backhaul modes for different TRPs permits thecoordination of transmission and reception between TRPs without crossinterference and can also enable implementation of the high frequencybackhaul link for TRPs with different beamforming capability. As anexample, some TRPs have larger numbers of communications beams in theirrespective complement of communications beams since some TRPs havedifferent limits on the number of simultaneous transmissions orreceptions beams that they are capable of performing.

FIGS. 9A-9C illustrate diagrams of backhaul modes of a first set ofbackhaul modes for a first TRP type, e.g., type A TRPs. Type A TRPs arecapable of sending and/or receiving on all communications beamssimultaneously. Diagram 900 (FIG. 9A) illustrate a first backhaul modeof type A TRPs where a TRP transmits using its full complement ofcommunications beams. Diagram 910 (FIG. 9B) illustrate a second backhaulmode of type A TRPs where the type A TRPs receive using their fullcomplement of communications beams. Diagram 920 (FIG. 9C) illustrate athird backhaul mode of type A TRPs where the type A TRPs are idle,performing neither transmissions nor receptions on any of theircommunications beams.

FIGS. 9D-9G illustrate diagrams backhaul modes of a second set ofbackhaul modes for second and third TRP types, e.g., types B and C TRPs.Diagram 930 (FIG. 9D) illustrate a first backhaul mode of types B and CTRPs where a TRP receives using a first set of its complement ofcommunications beams. Diagram 940 (FIG. 9E) illustrate a second backhaulmode of types B and C TRPs where a TRP transmits using a second set ofits complement of communications beams. Diagram 950 (FIG. 9F) illustratea third backhaul mode of types B and C TRPs where a TRP receives using athird set of its complement of communications beams. Diagram 960 (FIG.9G) illustrate a fourth backhaul mode of types B and C TRPs where a TRPtransmits using a fourth set of its complement of communications beams.It is noted that the configuration of sets of backhaul nodes and TRPtypes illustrated in FIGS. 9A-9G are for illustrative purposes only andare not meant to limit the scope or the spirit of the exampleembodiments.

The first set and the third set are mutually exclusive and when combinedcomprise the entirety of the full complement of communications beams.Similarly, the second set and the fourth set are mutually exclusive andwhen combined comprise the entirety of the full complement ofcommunications beams.

FIGS. 10A-10D illustrate diagrams of a portion of a communicationssystem highlighting TRPs operating in different example sets of backhaulmodes to facilitate a high frequency backhaul link. Within any giventime period, the backhaul mode of a TRP may be determined based on theposition of the TRP relative to its neighboring TRPs. A schedulingalgorithm may be used to determine the mode of the TRPs of thecommunications system, for example. The backhaul mode may also bedetermined based on the capabilities of the TRP. Diagram 1000 (FIG. 10A)illustrates the backhaul modes of the TRPs during a first time period.During the first time period, a first TRP 1005 (of Type C) is set tooperate in the third backhaul mode of the second set of backhaul modes(receive using a second set of communications beams). A first subset ofthe neighboring TRPs of first TRP 1005 (Type B TRPs), e.g., second TRP1007, third TRP 1009, and fourth TRP 1011, are set to operate in thefirst backhaul mode of the second set of backhaul modes (receive using afirst set of communications beams) and a second subset of theneighboring TRPs of first TRP 1005 (Type A TRPs), e.g., fifth TRP 1013,sixth TRP 1015, and seventh TRP 1017, are set to operate in the firstbackhaul mode of the first set of backhaul modes (transmit using theirfull complement of communications beams). As discussed previously, thesecond subset of the neighboring TRPs of first TRP 1005, the Type A TRPsmay be assigned different set of backhaul modes due to theircapabilities, which may differ from the capabilities of the first subsetof the neighboring TRPs of first TRP 1005 (Type B TRPs). It is notedthat the configuration of sets of backhaul nodes and TRP typesillustrated in FIGS. 10A-10D are for illustrative purposes only and arenot meant to limit the scope or the spirit of the example embodiments.

Diagram 1030 (FIG. 10B) illustrates the backhaul modes of the TRPsduring a second time period. During the second time period, first TRP1005 is set to operate in the first backhaul mode of the second set ofbackhaul modes (receive using the first set of communications beams). Afirst subset of neighboring TRPs of first TRP 1005 (Type B TRPs), e.g.,second TRP 1007, third TRP 1009, and fourth TRP 1011, are set to operatein the second backhaul mode of the second set of backhaul modes(transmit using the second set of communications beams) and the secondsubset of the neighboring TRPs of first TRP 1005, e.g., fifth TRP 1013,sixth TRP 1015, and seventh TRP 1017, are set to operate in the thirdbackhaul mode of the first set of backhaul modes (the TRPs go silent,neither transmit nor receive).

Diagram 1050 (FIG. 10C) illustrates the backhaul modes of the TRPsduring a third time period. During the third time period, first TRP 1005(Type B TRPs) is set to operate in the fourth backhaul mode of thesecond set of backhaul modes (transmit using the first set ofcommunications beams). A first subset of neighboring TRPs of first TRP1005, e.g., second TRP 1007, third TRP 1009, and fourth TRP 1011, areset to operate in the third backhaul mode of the second set of backhaulmodes (receive using the second set of communications beams) and thesecond subset of the neighboring TRPs of first TRP 1005, e.g., fifth TRP1013, sixth TRP 1015, and seventh TRP 1017, are set to operate in thethird backhaul mode of the first set of backhaul modes (the TRPs gosilent, neither transmit nor receive).

Diagram 1070 (FIG. 10D) illustrates the backhaul modes of the TRPsduring a fourth time period. During the fourth time period, first TRP1005 is set to operate in the second backhaul mode of the second set ofbackhaul modes (transmit using the second set of communications beams).A first subset of neighboring TRPs of first TRP 1005, e.g., second TRP1007, third TRP 1009, and fourth TRP 1011, are set to operate in thefourth backhaul mode of the second set of backhaul modes (transmit usingthe first set of communications beams) and the second subset of theneighboring TRPs of first TRP 1005, e.g., fifth TRP 1013, sixth TRP1015, and seventh TRP 1017, are set to operate in the second backhaulmode of the first set of backhaul modes (receive using their fullcomplement of communications beams).

Table 3 illustrates example backhaul modes for different TRP types, withX representing no communications, D representing downlinkcommunications, and U representing uplink communications.

TABLE 3 Example backhaul times for different TRP types. Cell TypeSub-frame 1 Sub-frame 2 Sub-frame 3 Sub-frame 4 A D full (mode A1) X(mode A3) X (mode A3) U full (mode A2) B U partial (mode 1) D partial(mode 2) U partial (mode 3) D partial (mode 4) C U partial (mode 3) Upartial (mode 1) D partial (mode 4) D partial (mode 2)

As with the previously discussed example embodiments, the time orderingof the subframes is unimportant, only the backhaul modes for the TRPsare synchronized with their neighboring TRPs. A different time order ofthe subframes (e.g., 1, 4, 2, and 3) may allow for TRP type A to usesubframes 2 and 3 for access since no backhaul beamforming is needed insubframes 2 and 3 for TRP type A.

According to an example embodiment, TDD subframes used for the highfrequency backhaul link are time multiplexed (using TDMA) with TDDsubframes used for access. Even if the spectrum is split using FDMA, theradio frequency (RF) beamforming chains at the TRPs may be time sharedbetween the high frequency backhaul link and the access to reducecomplexity and cost. According to an example embodiment, in order totime multiplex the TDD subframes used for the high frequency backhaullink (as generated in accordance with any of the example embodimentsregarding backhaul modes presented herein) with the TDD subframes usedfor access, the common portions of the TDD subframes used for access areused. Table 4 illustrates TDD frame configurations for 3GPP LTE-A. Thesubframes labeled “S” (subframe 1) are common for all TDD frameconfigurations. According to an alternative example embodiment, the TDDsubframes used for the high frequency backhaul link are inserted betweenTDD subframes used for access.

TABLE 4 TDD frame configurations for 3GPP LTE-A. Uplink- Downlink toDownlink Uplink Configura- Switch Subframe Number tion Periodicity 0 1 23 4 5 6 7 8 9 0 5 ms D S U U U D S U U U 1 5 ms D S U U D D S U U D 2 5ms D S U D D D S U D D 3 10 ms D S U U U D D D D D 4 10 ms D S U U D D DD D D 5 10 ms D S U D D D D D D D 6 5 ms D S U U U D S U U D

According to an example embodiment, the duration of a subframe used foraccess to carry the TDD subframes for high frequency backhaul linksupport is extended to accommodate TDD subframes used for high frequencybackhaul link support. Extending the access subframe may be needed toprovide adequate bandwidth. FIG. 11 illustrates an example framestructure 1100 with an extended subframe in the access frame, which isused to carry the TDD subframes for high frequency backhaul linksupport. In order to communicate at least one complete downlink anduplink subframe for the high frequency backhaul link, the extendedaccess subframe used to carry these backhaul subframes must be able tocarry at least one (1) subframe per backhaul mode. Therefore, to supportthe example embodiments shown in FIGS. 5 through 8, extension to supportat least 3 subframes is needed, while to support the example embodimentshown in FIGS. 9 through 10, an extension to support at least 4subframes is needed. It is noted that the extension may be greater thanthe minimum number of subframes to support additional high frequencybackhaul link information. Furthermore, the TDD frame format of thebackhaul sub-frames and the duration of the extended subframe may varydynamically to support dynamically varying data rates in differentdirections between TRPs. Alternatively, one complete downlink or uplinkTDD subframe for high frequency backhaul link may be supported. However,complete high frequency backhaul link information may not be conveyed inits entirety.

It is noted that because the high frequency backhaul link between TRPswill use a fixed communications beam direction (since the TRPs aregenerally stationary) as opposed to variable communications beamdirections used for the access, the beam-width of the communicationsbeams used for the high frequency backhaul link may be substantiallynarrower than those used for the access, thereby resulting in highersignal to noise ratios (SNRs), which in turn facilitates the use ofhigher level modulation schemes for the high frequency backhaul link(e.g., 256 QAM) than for the access (e.g., 16 QAM). Additionally,because the TRPs are generally stationary, lower sounding overhead isneeded for the high frequency backhaul link than for the access. Hence,on a per subframe basis, the high frequency backhaul link can achievemuch higher data rates than the access link, on the order of 2 to 2.5times faster. The greater data rates means that even when a TRP hasselected a TDD frame configuration for the access which has manydownlink subframes (D) (e.g., frame format 5) or uplink subframes (U)(e.g., frame format 0), much fewer subframes are needed to support thehigh frequency backhaul link for all UE data in each frame. FIG. 12illustrates TDD frame configurations 1200 for 3GPP LTE-A, highlightingframe format 0 and frame format 5. As shown in FIG. 12, frame format 0has more U subframes than D subframes (6 U vs 2 D), while frame format 5has more D subframes than U subframes (8 D vs 1 U). Even with suchsubframe imbalances, the higher data rates achievable in the highfrequency backhaul link results in a requirement of fewer high frequencybackhaul link subframes to support the data rates supported in theaccess link.

In communications systems where the access link and the high frequencybackhaul link operate at different frequencies (e.g., the configurationshown in FIG. 3A), the difference in the numerologies of the differentlinks (i.e., 3GPP LTE at 3 GHz for the access link and mmWave at 30 GHzfor the high frequency backhaul link may result in subframe durationdifferences on the order of 10 times) and the difference in theoperating frequencies may mean that the two frame structures may beentirely independent. It may be advantageous to make the timing betweenthe two different frame structures consistent to simplify implementationand to make the user data for the access link be available by way of thehigh frequency backhaul link in a timely manner. As an example,subframes for the high frequency backhaul link should occur withsufficient frequency to ensure that the user data is transferred betweenTRPs before it is needed.

FIG. 13 illustrates an example TDD frame format 1300 for supporting thehigh frequency backhaul link. FIG. 13 provides a detail view of Ssubframe 1305, which includes a downlink pilot time slot (DwPTS), a GP,and an uplink pilot time slot (UpPTS), of an access frame 1310. FIG. 13also displays a frame 1315 for the high frequency backhaul link. Avariety of different TDD frame formats are available and each TRPconnection may use a different subframe time period to meet theirrespective data rate requirements. Furthermore, the exact timingposition of frames of the high speed backhaul link is flexible. However,consistency in the timing may make implementation simpler.

Coverage areas with consistent shapes (hexagonal coverage areas) andconsistent sizes (all TRPs having the same sized coverage areas) havebeen used to present the general principle of the differentcommunications beam multiplexing techniques. However, in a real-worlddeployment, the coverage areas for the TRPs will not all be the sameshape and/or size. In general, the coverage area of each TRP will havesome arbitrary shape and size that is dependent upon the terrain andpropagation conditions. Additionally, each TRP may not have exactly 6neighbor TRPs.

FIG. 14 illustrates a generalized communications system 1400.Communications system 1400 includes a TRP X 1405 with an associatedcoverage area 1410. The shape of coverage area 1410 may depend upon theterrain (e.g., large structures or geographical features blockingsignals, wide open space allowing clear signal propagation, and so on)and propagation conditions. TRP X 1405 has Yx neighboring TRPs. Thenumber of neighboring TRPs depending upon the location of TRP X 1405with respect to communications system 1400 (e.g., system center, systemedge, and so on), the density of users, the presence or lack ofinterference, and so forth.

According to an example embodiment, in a generalized communicationssystem, each TRP has an integer number of backhaul modes of operationfor communicating on the high frequency backhaul link. Within eachbackhaul mode of operation, a TRP performs downlink transmissions oruplink receptions and not both downlink and uplink. Between backhaulmodes of operation, a TRP can either switch communications mode, e.g.,from downlink to uplink or uplink to downlink, or remain in the samecommunications mode, e.g., downlink to downlink or uplink to uplink.Every TRP uses the same backhaul modes of operation, but different TRPtypes perform different backhaul modes in a given time period. Theassignment of the backhaul modes is made based on TRP type, where TRPtype may be assigned using a scheduling algorithm, for example. The TRPssequentially cycle through the backhaul modes.

According to an example embodiment, in a generalized communicationssystem, each TRP has 3 backhaul modes of operations for communicating onthe high frequency backhaul link. In a first backhaul mode, the TRPcommunicates (sends or receives) with all of its neighboring TRPs usingits full complement of communications beams. In a second backhaul mode,the TRP communicates (receives or sends) with a first set of itsneighboring TRPs using a first set of its communications beams, and in athird backhaul mode, the TRP communicates (receives or sends) with itsneighboring TRPs using a second set of its communications beams. Thesecond and third backhaul modes may be referred to as partial modessince they involve communications with a portion of the neighboringTRPs. A combination of the first set of communications beams and thesecond set of communications beams make up the full complement ofcommunications beams. Furthermore, the first set of communications beamsand the second set of communications beams may be mutually exclusive. Itis noted that there may be more than 3 backhaul modes with more than 2partial modes. However, the more than 2 partial modes, when combined,will cover all of the neighboring TRPs.

According to an example embodiment, in a generalized communicationssystem, a first backhaul mode comprises a TRP X transmitting to all ofits neighboring TRPs using its full complement of communications beams,a second backhaul mode comprises the TRP X receiving from a first set ofits neighboring TRPs on a first set of communications beams, and a thirdbackhaul mode comprises the TRP X receiving from a second set of itsneighboring TRPs on a second set of communications beams. The first setand the second set of neighboring TRPs make up all of the neighboringTRPs of TRP X and may be mutually exclusive. The first set and thesecond set of neighboring TRPs may be unequal in size, for example, ifthere is an odd number of neighboring TRPs. The first set and the secondset of communications beams make up the full complement ofcommunications beams of TRP X and may be mutually exclusive. Theassignment of the TRPs may be static, semi-static, or dynamical innature. The corresponding number of subframes required may be dependenton actual deployment.

According to an example embodiment, in a generalized communicationssystem, a first backhaul mode comprises a TRP X receiving from all ofits neighboring TRPs using its full complement of communications beams,a second backhaul mode comprises the TRP X transmitting to a first setof its neighboring TRPs on a first set of communications beams, and athird backhaul mode comprises the TRP X transmitting to a second set ofits neighboring TRPs on a second set of communications beams. The firstset and the second set of neighboring TRPs make up all of theneighboring TRPs of TRP X and may be mutually exclusive. The first setand the second set of neighboring TRPs may be unequal in size, forexample, if there is an odd number of neighboring TRPs or if theneighboring TRPs are not evenly distributed. The first set and thesecond set of communications beams make up the full complement ofcommunications beams of TRP X and may be mutually exclusive.

According to an example embodiment, in a generalized communicationssystem, some TRP types have different backhaul modes that are determinedand assigned based on the TRP type as well as their individualbeamforming capabilities, where at least some of the different TRP typescycle through different sets of backhaul modes. If there are differencesin the number of modes per different set of backhaul modes, TRPs usingthe set of backhaul modes with fewer modes may remain idle after theyhave cycled through their respective set of backhaul modes to permit theother TRPs using the different sets of backhaul modes to complete theircycles. Although there are different sets of backhaul modes, all TRPs ofa TRP type assigned to a set of backhaul modes will use the same set ofbackhaul modes. Furthermore, all TRPs cycle through the backhaul modesat the same rate. The use of different sets of backhaul modes permitsthe implementation of the high frequency backhaul link for TRPs withdifferent beamforming capability. As an example, some TRPs have largernumbers of communications beams in their respective complement ofcommunications beams. As another example, some TRPs have differentlimits on the number of simultaneous transmissions or receptions thatthey are capable of performing.

According to an example embodiment, in a generalized communicationssystem, a first type of TRP is assigned a set of 3 backhaul modes andmore than one second types of TRP are assigned a set of 4 backhaulmodes. The set of 3 backhaul modes may include a first backhaul modewhere a TRP transmits to all of its neighboring TRPs using its fullcomplement of communications beams, a second backhaul mode where the TRPreceives from all of its neighboring TRP using its full complement ofcommunications beams, and a third backhaul mode where the TRP remainsidle. The set of 4 backhaul modes may include a first backhaul modewhere a TRP transmits to a first set of neighboring TRPs using a firstset of communications beams, a second backhaul mode where the TRPreceives from a first set of neighboring TRPs using a first set ofcommunications beams, a third backhaul mode where the TRP transmits to asecond set of communications beams, and a fourth backhaul mode where theTRP receives from a second set of neighboring TRPs using a second set ofcommunications beams. It is noted that some implementations may includegreater numbers of partial modes.

The assignment of which TRPs will be in which backhaul mode for eachsubframe of the TDD backhaul frame may depend upon the deployment, aswell as how the neighboring TRPs are located in space. Examples withregular deployments in a hexagonal communications system are discussedabove. The backhaul mode to subframe mapping for each TRP may beperformed as part of a TDD backhaul frame configuration.

The mapping may be performed statically during network planning. EachTRP may be assigned a TRP specific TDD backhaul frame configuration withthe respective backhaul modes. The configuration may be stored and laterretrieved from memory or database.

The mapping may be performed semi-statically. A newly deployed TRP mayperform a beam sweep to find all of its neighboring TRPs and theirrespective identifiers. The newly deployed TRP may report to a TDDbackhaul frame configuration entity, the report may include identifiersof the neighboring TRPs (and optionally, beam indices of the newlydeployed TRP associated with each of the neighboring TRPs, e.g., beamdirections), this is referred to as neighbor list reporting; andbeamforming capability of the newly deployed TRP, this is referred to asTRP capability reporting. The newly deployed TRP receives TRP specificTDD backhaul frame configuration with associated backhaul modes from theTDD backhaul frame configuration entity. The TDD backhaul frameconfiguration entity may be a network entity dedicated to configurationor it may be collocated with an existing network entity.

The mapping may be performed dynamically (i.e., at a greater frequencythan semi-static). A network controlling entity may dynamically informeach TRP of its TRP specific TDD backhaul frame structure. Theinformation provided by the network controlling entity may be based upona chosen TDD frame for the access for each TRP; and/or an updatedneighbor list reports from each TRP, which may be useful when the TRPsare turned on or off for special events (concerts, sports, conventions,etc.), turned on or off due to load, or when a TRP is non-stationary(vehicles, buses, trains, etc.).

Communications between the network controlling entity and each TRP tosemi-statically or dynamically assign the TDD backhaul frame structureto each TRP may occur over a dedicated TRP to network controlling entityconnection (may be either wired or wireless). This connection may besimple to implement when an mmWave backhaul is used to complement aregular X2 interface. It is noted that only low data rates are neededfor the connection.

FIG. 15 illustrates example ways 1500 for a TRP to obtain TDD backhaulframe configurations. TRP X 1505 may obtain the TDD backhaul frameconfiguration from a memory 1510, a network entity 1515, or from aneighboring TRP 1520 (such as a master TRP).

As an illustrative example, parameters of the TDD backhaul frameconfiguration includes at least one of the following:

-   -   TDD frame format index: this option assumes a fixed set of        available formats (i.e., 2, 4, 8, 12, 16, and so on) and incurs        very low overhead;        -   Alternatively, a frame length (in subframes, for example)            may be specified for each access frame and mode (1, 2, 3,            and so forth) or subframe type (downlink-full, uplink-full,            downlink-partial, uplink-partial, and so on) for each            subframe in the TDD backhaul frame;    -   Indices of the TRPs (or angular directions) for the full        subframes;    -   Indices of the TRPs (or directions) for the separate partial        subframes or modes.

FIGS. 16A and 16B illustrate example deployments for urban areas. FIG.16A is presented in A. Goldsmith et al, “A Measurement-based Model forPredicting Coverage Areas of Urban Microcells,” IEEE Journal on Sel.Areas in Communications, Vol. 11, No. 7, September 1993, pp. 1013-11023,which is hereby incorporated herein by reference and illustrates signalpower level of a rectangular urban deployment. FIG. 16B is presented in3GPP RAN 1 WG 1 Meeting #84-R1 160924, “Diamond Shaped Cell Layouts forAbove 6 GHz Channel Modeling”, which is hereby incorporated herein byreference and illustrates a diamond shaped urban deployment with 9sites.

FIG. 17 illustrates a flow diagram of example operations 1700 occurringin a network entity performing backhaul mode to TDD backhaul subframemapping. Operations 1700 may be indicative of operations occurring in anetwork entity, such as a TDD frame configuration entity or a networkcontrolling entity, as the network entity performs backhaul mode to TDDbackhaul subframe mapping.

Operations 1700 begin with the network entity receiving neighbor listsand TRP capability reports from TRPs (block 1705). The neighbor listsand TRP capability reports may be received from all TRPs of thecommunications system. Alternatively, the neighbor lists and TRPcapability reports are received from newly deployed TRPs or TRPs, whichhave changed configuration. As an example, when a TRP determines thatits neighboring TRPs have changed, the TRP sends a neighbor list and/orTRP capability report. As another example, when the capability of a TRPchanges, the TRP sends a TRP capability report and/or neighbor list.Alternatively, the network entity receives information regarding theTRPs during network planning. The network entity assigns TRP types tothe TRPs (block 1710). The assignment of the TRP types may be performedusing a scheduling algorithm based on a topology of the communicationssystem. Alternatively, the assignment of the TRP types may be performedusing a scheduling algorithm that also considers the TRP capabilities.The network entity assigns backhaul modes to the TRPs in accordance withthe assigned TRP types (block 1715). The network entity assigns TDDbackhaul frame configurations to the TRPs in accordance with theassigned TRP types (block 1720). The network entity saves the TDDbackhaul frame configuration and backhaul modes (block 1725). The TDDbackhaul frame configuration and backhaul modes may be save to memory ordatabase. Alternatively, the TDD backhaul frame configuration andbackhaul modes may be provided directly to the TRPs.

FIG. 18 illustrates a flow diagram of example operations 1800 occurringin a TRP communicating using a high frequency backhaul link. Operations1800 may be indicative of operations occurring in a TRP that iscommunicating using a high frequency backhaul link.

Operations 1800 begin with the TRP determining TDD backhaul frameconfiguration and backhaul modes (block 1805). The TDD backhaul frameconfiguration and backhaul modes may be retrieve from memory ordatabase, retrieved from a network entity, or a neighboring TRP (such asa master TRP). Alternatively, the backhaul frame configuration andbackhaul modes may be instructed directly in a message received from anetwork entity that made the assignment. During a time period, the TRPcommunicates using the high frequency backhaul in a manner commensuratewith a backhaul mode corresponding to the time period (block 1810). TheTRP performs a check to determine if the time period is over (block1815). If the time period is not over, the TRP continues communicatingas in block 1810. If the time period is over, the TRP switches to a nexttime period (block 1820) and returns to block 1810 to communicate inaccordance with a backhaul mode corresponding to the next time period.

FIG. 19 illustrates a block diagram of an embodiment processing system1900 for performing methods described herein, which may be installed ina host device. As shown, the processing system 1900 includes a processor1904, a memory 1906, and interfaces 1910-1914, which may (or may not) bearranged as shown in FIG. 19. The processor 1904 may be any component orcollection of components adapted to perform computations and/or otherprocessing related tasks, and the memory 1906 may be any component orcollection of components adapted to store programming and/orinstructions for execution by the processor 1904. In an embodiment, thememory 1906 includes a non-transitory computer readable medium. Theinterfaces 1910, 1912, 1914 may be any component or collection ofcomponents that allow the processing system 1900 to communicate withother devices/components and/or a user. For example, one or more of theinterfaces 1910, 1912, 1914 may be adapted to communicate data, control,or management messages from the processor 1904 to applications installedon the host device and/or a remote device. As another example, one ormore of the interfaces 1910, 1912, 1914 may be adapted to allow a useror user device (e.g., personal computer (PC), etc.) tointeract/communicate with the processing system 1900. The processingsystem 1900 may include additional components not depicted in FIG. 19,such as long term storage (e.g., non-volatile memory, etc.).

In some embodiments, the processing system 1900 is included in a networkdevice that is accessing, or part otherwise of, a telecommunicationsnetwork. In one example, the processing system 1900 is in a network-sidedevice in a wireless or wireline telecommunications network, such as abase station, a relay station, a scheduler, a controller, a gateway, arouter, an applications server, or any other device in thetelecommunications network. In other embodiments, the processing system1900 is in a user-side device accessing a wireless or wirelinetelecommunications network, such as a mobile station, a user equipment(UE), a personal computer (PC), a tablet, a wearable communicationsdevice (e.g., a smartwatch, etc.), or any other device adapted to accessa telecommunications network.

In some embodiments, one or more of the interfaces 1910, 1912, 1914connects the processing system 1900 to a transceiver adapted to transmitand receive signaling over the telecommunications network. FIG. 20illustrates a block diagram of a transceiver 2000 adapted to transmitand receive signaling over a telecommunications network. The transceiver2000 may be installed in a host device. As shown, the transceiver 2000comprises a network-side interface 2002, a coupler 2004, a transmitter2006, a receiver 2008, a signal processor 2010, and a device-sideinterface 2012. The network-side interface 2002 may include anycomponent or collection of components adapted to transmit or receivesignaling over a wireless or wireline telecommunications network. Thecoupler 2004 may include any component or collection of componentsadapted to facilitate bi-directional communication over the network-sideinterface 2002. The transmitter 2006 may include any component orcollection of components (e.g., up-converter, power amplifier, etc.)adapted to convert a baseband signal into a modulated carrier signalsuitable for transmission over the network-side interface 2002. Thereceiver 2008 may include any component or collection of components(e.g., down-converter, low noise amplifier, etc.) adapted to convert acarrier signal received over the network-side interface 2002 into abaseband signal. The signal processor 2010 may include any component orcollection of components adapted to convert a baseband signal into adata signal suitable for communication over the device-side interface(s)2012, or vice-versa. The device-side interface(s) 2012 may include anycomponent or collection of components adapted to communicatedata-signals between the signal processor 2010 and components within thehost device (e.g., the processing system 1900, local area network (LAN)ports, etc.).

The transceiver 2000 may transmit and receive signaling over any type ofcommunications medium. In some embodiments, the transceiver 2000transmits and receives signaling over a wireless medium. For example,the transceiver 2000 may be a wireless transceiver adapted tocommunicate in accordance with a wireless telecommunications protocol,such as a cellular protocol (e.g., long-term evolution (LTE), etc.), awireless local area network (WLAN) protocol (e.g., Wi-Fi, etc.), or anyother type of wireless protocol (e.g., Bluetooth, near fieldcommunication (NFC), etc.). In such embodiments, the network-sideinterface 2002 comprises one or more antenna/radiating elements. Forexample, the network-side interface 2002 may include a single antenna,multiple separate antennas, or a multi-antenna array configured formulti-layer communication, e.g., single input multiple output (SIMO),multiple input single output (MISO), multiple input multiple output(MIMO), etc. In other embodiments, the transceiver 2000 transmits andreceives signaling over a wireline medium, e.g., twisted-pair cable,coaxial cable, optical fiber, etc. Specific processing systems and/ortransceivers may utilize all of the components shown, or only a subsetof the components, and levels of integration may vary from device todevice.

Although the present disclosure and its advantages have been describedin detail, it should be understood that various changes, substitutions,and alterations can be made herein without departing from the spirit andscope of the disclosure as defined by the appended claims.

What is claimed is:
 1. A method for operating a network entity in acommunications system, the method comprising: transmitting, by thenetwork entity, a first signal indicating backhaul communication modesfor a transmission-reception point (TRP), each of the backhaulcommunication modes configuring the TRP to use a corresponding subset ofbeams of the TRP for backhaul signal communications between the TRP anda corresponding subset of TRPs in a set of TRPs, the correspondingsubset of beams of the TRP selected from a full set of beams of the TRP;and transmitting, by the network entity, a second signal indicatingbackhaul frame configurations to the TRP, each of the backhaul frameconfigurations configuring the TRP to use a corresponding arrangement ofsubframes for backhaul signal communications between the TRP and acorresponding subset of TRPs in the set of TRPs.
 2. The method of claim1, wherein the full set of beams includes a first corresponding subsetof beams configured for backhaul signal communications between the TRPand a first corresponding subset of TRPs and a second correspondingsubset of beams configured for backhaul signal communications betweenthe TRP and a second corresponding subset of TRPs, the firstcorresponding subset of beams being mutually exclusive from the secondfirst corresponding subset of beams.
 3. The method of claim 2, whereinthe second corresponding subset of TRPs is mutually exclusive from thefirst corresponding subset of TRPs.
 4. The method of claim 1, whereineach of the backhaul communication modes mode further indicates asynchronized order of transmitting and receiving a backhaul signal bythe TRP.
 5. The method of claim 1, further comprising assigning, by thenetwork entity, a TRP-type to the TRP using a scheduling algorithm, thescheduling algorithm assigning the TRP-type in accordance with atopology of the communications system or a capability of the TRP.
 6. Themethod of claim 5, further comprising assigning, by the network entity,each of the backhaul communication modes mode to the TRP in accordancewith a capability of the TRP or the TRP-type of the TRP.
 7. The methodof claim 1, wherein one of the backhaul frame configurations configuresthe TRP to use a special subframe for backhaul signal communicationsbetween the TRP and at least one corresponding set of TRPs, the specialsubframe subframes not being used for access communications between theTRP and one or more user equipments (UEs) accessing the communicationssystem.
 8. The method of claim 1, further comprising receiving, by thenetwork entity, neighbor lists or TRP capability reports from at leastone TRP in the set of TRPs.
 9. The method of claim 8, wherein theneighbor lists or capability reports indicate that the at least one TRPis a newly deployed TRP, a reconfigured TRP, or has detected a change incapabilities or a change in neighboring TRPs.
 10. The method of claim 1,further comprising receiving information regarding neighbor lists andTRP capability reports during network planning.
 11. The method of claim1, wherein the network entity is a time division duplexed (TDD) frameconfiguration entity or a network controlling entity.
 12. The method ofclaim 1, wherein transmitting the second signal further comprisesdynamically assigning, by the network entity, a respective time divisionduplexed (TDD) backhaul frame structure for backhaul signalcommunications between the TRP and each of the corresponding subsetssubset of TRPs.
 13. The method of claim 1, wherein transmitting thesecond signal further comprises semi-statically assigning, by thenetwork entity, a respective time division duplexed (TDD) backhaul framestructure for backhaul signal communications between the TRP and each ofthe corresponding subsets subset of TRPs.
 14. The method of claim 1,wherein the second signal is transmitted over a dedicated connectionbetween the network entity and the TRP.
 15. A network entity in acommunications system, the network entity comprising: a non-transitorymemory storage comprising instructions; and a processor in communicationwith the non-transitory memory storage, wherein the processor executesthe instructions to: transmit a first signal indicating backhaulcommunication modes for a transmission-reception point (TRP), each ofthe backhaul communication modes configuring the TRP to use acorresponding subset of beams of the TRP for backhaul signalcommunications between the TRP and a corresponding subset of TRPs in aset of TRPs, the corresponding subset of beams of the TRP selected froma full set of beams of the TRP; and transmit a second signal indicatingbackhaul frame configurations to the TRP, each of the backhaul frameconfigurations configuring the TRP to use a corresponding arrangement ofsubframes for backhaul signal communications between the TRP and acorresponding subset of TRPs in the set of TRPs.
 16. The network entityof claim 15, wherein the full set of beams includes a firstcorresponding subset of beams configured for backhaul signalcommunications between the TRP and a first corresponding subset of TRPsand a second corresponding subset of beams configured for backhaulsignal communications between the TRP and a second corresponding subsetof TRPs, the first corresponding subset of beams being mutuallyexclusive from the second corresponding subset of beams.
 17. The networkentity of claim 16, wherein the second corresponding subset of TRPs ismutually exclusive from the first corresponding subset of TRPs.
 18. Thenetwork entity of claim 15, wherein each of the backhaul communicationmodes mode further indicates a synchronized order of transmitting andreceiving a backhaul signal by the TRP.
 19. The network entity of claim15, wherein the programming further includes instructions to assign aTRP-type to the TRP using a scheduling algorithm, the schedulingalgorithm assigning the TRP-type in accordance with a topology of thecommunications system or a capability of the TRP.
 20. The network entityof claim 19, wherein the programming further includes instructions toassign each of the backhaul communication modes mode to the TRP inaccordance with a capability of the TRP or the TRP-type of the TRP. 21.The network entity of claim 15, wherein one of the backhaul frameconfigurations configures the TRP to use a special subframe for backhaulsignal communications between the TRP and at least one corresponding setof TRPs, the special subframe not being used for access communicationsbetween the TRP and one or more user equipments (UEs) accessing thecommunications system.
 22. The network entity of claim 15, wherein theprogramming further includes instructions to receive neighbor lists orTRP capability reports from at least one TRP in the set of TRPs.
 23. Thenetwork entity of claim 22, wherein the neighbor lists or capabilityreports indicate that the at least one TRP is a newly deployed TRP, areconfigured TRP, or has detected a change in capabilities or a changein neighboring TRPs.
 24. The network entity of claim 15, furthercomprising receiving information regarding neighbor lists and TRPcapability reports during network planning.
 25. The network entity ofclaim 15, wherein the network entity is a time division duplexed (TDD)frame configuration entity or a network controlling entity.
 26. Thenetwork entity of claim 15, wherein transmitting the second signalfurther comprises dynamically assigning, by the network entity, arespective time division duplexed (TDD) backhaul frame structure forbackhaul signal communications between the TRP and each of thecorresponding subsets subset of TRPs.
 27. The network entity of claim15, wherein the instructions to transmit the second signal includeinstructions to: semi-statically assign a respective time divisionduplexed (TDD) backhaul frame structure for backhaul signalcommunications between the TRP and each of the corresponding subsetssubset of TRPs.
 28. The network entity of claim 15, wherein the secondsignal is transmitted over a dedicated connection between the networkentity and the TRP.